Apparatus for molding plastic material



APPARATUS FOR MOLDING PLASTIC MATERIAL Original Filed April 5, 1928 2Sheets-Sheet l Nov. 27, 1934. v, G, APPLE A1,982,279

APPARATUS FOR MOLDING PLASTIC MATERIAL original Filed April 5, 1928 2sheets-sheet 2 i 5% ai NVENTOR Patented Nov. 27, 1934 UNITED STATESPATENT OFFICE Vincent G.

Apple, Dayton,

Ohio; Herbert F.

Apple, Edward M. Apple and Gourley Darroch, executors of said Vincent G.Apple, deceased Original application April 5, 1928, Serial No.

267,782. Divided and this application January 25, 1930, Serial No.423,564

3 Claims.

This invention is a division of my copending application Serial No.267,782, led April th, 1928 and relates to apparatus for molding plasticmaterial, and is particularly adapted to mold a hous- 5 ing of plasticmaterial about the core and coils of a dynamo electric machine element.

By so proportioning the core and coils as to leave considerable spacebetween adjacent poles, and by so proportioning the core slots that theo coil sides do not altogether fill the slots, the insulating materialwhich is being molded about the coils at one end of the core may beforced through the space between the poles and through the unfilled partof the slots to the other end of the core to form a one piece mass ofinsulation which covers the coil ends and sides and which consists ofthe two large masses at the ends of the core joined by integral strutsof the same material, and it is one object of this invention to providea mold to facilitate placing insulation about the assembled core andcoils in this manner.

Another object is to so construct the mold as to form air ducts in theinsulation mass extending lengthwise therethrough.

I attain these and other objects by the structure shown in theaccompanying drawings wherein- Fig. 1 is a plan of one of the corelamin.

Fig. 2 shows the core, coils and terminals assembled.

3 Fig. 3 is a cross section through the mold taken to cut the fieldelement therein at 3-3 of Figs. 1 and 7.

Fig. 4 shows the center plug of the mold in perspective.

Fig. 5 is a cross section taken at 5-5 of Figs. 1 and 7.

Fig. 6 is a cross section taken at 6-6 of Figs. l and 7.

Fig. 7 is a top View of the nished field element.

Fig. 8 is an elevation of the finished field element Fig. 9 is a bottomView of the finished field element. f

Similar numerals refer to similar parts throughout the several views.

To produce a field element which embodies my improvements I cut fromsuitable sheet magnetic material a plurality of lamin 10, Fig. 1,slotted for a 6 pole winding having three coils 11, 12 and 13, Fig. 2per pole. Each pole comprises ve teeth 14, 15, 15, 16, 16, separated bywinding slots 17, 17, 18, 18. The poles in turn are separated by therelatively wide spaces 19, 19, etc.

Openings 20 which are adapted to later pro- 55 `vide attaching boltholes 21 Fig. 6 are placed at the center of each pole where the magneticux divides, so that they remove the least needed portion of the yokematerial. Other openings 22 are placed midway between poles, and after asumcient number of laminas are assembled to compose a core 23 Fig. 2,openings 22 are lined with tubular insulators 24 (see Fig. 3) so thatbrush terminal stampings 25 and line terminal posts 26 may be attachedto the core by screws 27, or other suitable fastening means, and yet beelectrically insulated therefrom, the two outside lamina: 28 being alsoof insulating material. (See also Fig. 5.)

Fig. 2 shows the core after the coils are placed and the line and brushterminals attached. The ends of the coils are joined to the terminalsnear their point of support on the core, as at 29, 29, etc., so that aslight deflection of the terminals during the subsequent moldingoperation will not impair the joints between the wires and theterminals.

Whether the coils Fig. 2 should be impregnated with insulating varnishor the like before the structure is placed in the mold wherein thehousing is formed depends somewhat on the fineness of the wire in thecoils, the covering on the wire, the degree of fluidity to which theinsulation from which the housing is to be molded may be brought, etc.When, as in the instant case, no impregnation is required the structureFig. 2 is ready to have the housing molded thereto and is accordinglyplaced and supported in a mold as shown in Fig. 3, which is a crosssection so taken through the mold as to cut the eld element at 3 3 ofFigs. 1 and 7.

The mold Fig. 3 comprises three main parts, the body 30, the plug 31,shown also in perspective in Fig. 4, and the plunger 32. A tubularmembery 33 (see also Fig. 9) keeps core 23 raised, before the insulationis placed, so that ends of the coils do not rest on the bottom of themold. Member 33 has outwardly diverging holes 34 through which the massof molded insulation in the finished housing may extend to bind it to,and make it a part of the structure, and, if desired, member 33 may befurther secured to the core by welding, or by bolts, screws, rivets orother fastening means. Lateral pull bars 35, squared at their innerends, .extend inwardly through the wall of body 30 through the squarebrush pockets 36 of brush terminal stampings 25 to hold them correctlylocated and to exclude molded insulation therefrom, and also to keep thecore from rising in the mold, the threaded sleeve 37, into which brushspring caps may later be screwed, being supported on threaded tubes 38which enter through correspondingly threaded 110 holes in the mold bodyand surround the rounded stems of the bars 35.

By reference to Fig. d it will be seen that plug 31 is a cylinder havingan opening 39 adapted to receive plunger 32, the outside having a seriesof small axially extending keys corresponding to, but slightly narrowerthan the inner ends oi the winding slots in lamina 10, and a lessernumber of larger keys 41 corresponding to, but con- .siderably smallerthan the spaces 19 between coils 0f adjacent poles and extending axiallytherebetween to the lower end of the plug and there ending in lugs 42which are adapted to form passages in the insulation extending radiallyoutward and communicating with openings 43 in tubular member 33. (SeeFig. 3.)

Keys 4l, being slightly narrower and considerably less in height thanspaces 19, leave apertures lill, Fig. 3 of considerable size between thesurfaces of the keys and the wound structure, through which theinsulation may pass when the Ahousing in being znolded,'frorn the'largermass at the upper end oi the core to supply the lesser mass at the lowerend, the insulation remaining inthese apertures after molding iseffected being hardened along with the larger masses at opposite ends ofthe core to assist in tying them one mass to the other and consequentlyto the core. Recesses 45 admit the ends of pockets 35 and the widerportions 46 of the recesses permit insulation to surroundV a portion or"each pocket.

When the structure'Fig. 2 has been placed in the mold Fig. 3, andsupported therein as indicated, plunger '32 is removed, the insulatione7 placed in opening 39, then the plunger returned. It is readily seenthat when the plunger is foiped upward the insulation will rst iill thelargei` cavity 43 at the upper end of the mold and then ow through theaxially extending apertures fia `between keys il and spaces i9 to ll thecavity 49 at the lower end.

After the insulation 4'! is forced from opening 39 into cavities 48 and49 it is hardened by what ever process the nature of the insulationrequires etc., left in the molding by the small keys i0" of the plug 3l,and the larger lieyways Wi, 54, etc., left by the larger keys 4l. In acompleted dynamo electric machine these keyways serve as ducts throughwhich a cooling medium may move axially through the field element, thenradially through the grooves 55, 55, etc., to the openings 3 in tubularmember 33, and the material remaining in the axially extending passagesle between the keys Lll and the spaces Ecrin a series of channel shapedstruts which resist tension brought to bear on the structure.

Tubular member 33 which served to locate vcore 23 in the mold now servesas a protective armor at the lower end of the core and provides theannular rib which is usually required to concentrically locate an endmember carrying the armature shaft bearings. rlhe threaded sleeves 3'?,now rigidly imbedded in the bosses 50, will'take the wear incident tothe screwing in and out of the usual screw caps which may be employed toclose the brush pockets.

The mold herein shown and described embodies a feature covered in mycopending application Serial llo. 262,45), filed March 17th, 1928,namely that of forcing the insulation against the bottom of the stockcavity to compel it to move laterally of the movement oi the plunger, sothat unfluxed material may not be pressed directly against the coils asin conventional molds, but it is apparent that the features sought toVbe covered by the present application may be embodied in a mold of theconventional type, or in a mold of a different type, and while in theforegoing I have shown and described a structure embodying myimprovements, 'departures therefrom, such as altering the number ofpoles, using a solid instead of a laminated core, a concentrated insteadoi a distributed pole, and many others may obviously be brought withinthe scope of the invention, which to further dennel claim;-

l. A mold for forming a housing of moldable material about the woundportions oi the core of a dynamo electric machine element, said moldIcomprising, a body having a cavity fitted closely to the outside of thecore, a central plug fitted closely vto the bore of said core, a numberof pull bars having squared inner ends extending later-v ally inwardfrom the mold body into said cavity, to form pockets for brushes andbrush springs in the wall oi' said housing and being laterallywithdrawable through the mold body to iorm said pockets Yafter saidhousing is molded, and threadedtubes surrounding a rounded part of saidpull bars threaded into the mold body and extending into said cavity.

material about a wound dynamo electric machine core, a hollow memberhaving its interior surface shaped like the outer surface of thefinished housing, a second member having its exterior suri'ace shapedlike the inside of the finished housing held appropriately spaced withinthe first said member, a plunger for forcing inoldable material into thespace between the two said members in l alignment with the said members,anda'plurelay oi' pull bars having their axes at right angles to theaxis of the said plunger extending through the wall ot' saidhousing andsupported at their inner ends in pockets in said second member. 3. Formaking a dynamo electric inachineelement comprising a body oi' moldedinsulation in thev iorin or" an inverted cup, having a thin bottom butheavier side walls, and a hollow magnetizable core and a fragile windingimbedded in said side walls, apparatus comprising, in combination, amold body having ya cavity extending from the bottom upwardcorresponding to the exterior of said inver ed cup, a mold corecorresponding to said cup, and a plunger movable vertically upward insaid stock: chamber to such an extent as will torce the Ventire volumeof unrnolded plastic insulation completely from said stock chamber,laterally over the upper edge oi said4 mold core and downwardly aroundsaid mold core and around said` magnetizable core and winding.

VINCENT G. lAlEPLE.

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